Formula 2 champion Luciano Bacheta and last week's GP2 testing pacesetter Tom Dillmann will drive for new GP2 team Russian Time when testing resumes at Barcelona on Tuesday.
The test will be Bacheta's first run in a GP2 car.
The 22-year-old Briton won the final season of F2's latest incarnation in 2012.
Dillmann's Russian Time call-up comes a week after he set the pace for Hilmer Motorsport, another new GP2 entrant, at the opening winter test at Jerez.
A GP2 race-winner with Rapax in 2012, 23-year-old Frenchman Dillmann has yet to secure a deal for this season.
GP2 announced on Monday morning that Russian Time had bought long-time frontrunner iSport. AUTOSPORT revealed last month that iSport had decided to pull out of GP2 rather than risk financial problems this season.